<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width,initial-scale=1.0">
    <title>demo</title>
    <script src="a.js"></script>
    <script src="b.js"></script>
</head>
<body>
<script>
    // 从上到下解析,所以是b.js里面的
    console.log(star)
    // 模块化解决的问题: JavaScript程序在全局空间中变量被污染的问题




</script>
</body>
</html>